The patent situation is not 100% clear. It is hard to verify exactly how many patents are left that are still applicable, if any are at all. You'll need many hours of work and plenty of fees to good lawyers before you can verify such a thing. What I am sure of is that when Frank finally finds time away from his work, none of these patents will matter much They'll expire long before

For all those who wonder what the situation is, the programmer is busy with his important work. You have the option of giving up and moving to another format, or waiting. After all, there's no other lossy format that comes even close to MPC at medium/high bitrates. If you want to enjoy music the way it sounds on the CD, either wait for MPC development to speed up (maybe next year) or move to lossless (FLAC, Wavpack, Monkey's Audio)